1. Field of the Invention
The present invention relates to surgical devices for repair of split portions of tissue. In particular, the invention is directed to a sternum buckle applier for applying a buckle with attached strap about split portions of a sternum to maintain the portions in adjacent contacting relationship during healing. The invention is also directed to a buckle for use with the applier.
2. Description of the Prior Art
During surgery that involves a median sternotomy, e.g., open heart surgery, the sternum is split longitudinally to allow access to the organs within the thoracic cavity. Upon completion of the surgery, the sternum is rejoined and closed securely. For proper healing to occur, the split sternum portions are preferably engaged in face-to-face relationship and compressed together while the sternum heals.
Traditional methods for closing a sternum involve securing steel wires around or through the sternum halves and approximating the sternum by twisting the wires together.
Recently, a certain amount of emphasis has been directed towards the use of band or strap assemblies for sternum repair. Such assemblies typically include a locking mechanism which secures a strap in a closed looped configuration about the sternum portions. One example of an assembly of this type is described in U.S. Pat. No. 4,813,416 and includes a banding assembly having a curved surgical needle, an attached thin flat stainless steel band and a buckle mechanism. The sternum halves are brought to abutting closure by looping the band in position around or through the sternum portions and securing the band within the buckle mechanism.
While utilization of steel wires and strap assemblies have been widely accepted for sternum repair, certain shortcomings with these devices are apparent. The use of steel wires presents problems to the surgeon during the operation and to the patient after closure is completed. Steel wires are difficult to maneuver and place around the sternum. The wire edges are often sharp and can easily pierce through undesired areas including tissue surrounding the sternum area or the surgeon's gloves or fingers.
The strap assemblies known heretofore incorporate buckle mechanisms which are relatively structurally complex. For example, the buckle mechanism described in U.S. Pat. No. 4,813,416 includes a saddle part, interned flanges disposed on opposing sides of the saddle part and a loop segment. The saddle part and interned flanges define a band slide through course for reception of a portion of the band. A spring leaf extends upwardly from the loop segment through a slot in the saddle part. The tip end of the spring leaf is narrowed to define a spring tooth or projection which projects through an aperture formed in the band to maintain the closed band loop in a locked configuration.
A further disadvantage of conventional buckle assemblies for sternum closure is that they are generally difficult to apply about the sternum. This difficulty is attributed in part to the relative small size of the buckle, which presents handling and maneuvering problems to the surgeon during use. Further, the locking mechanisms incorporated therein usually involve some form of manual intervention in order to be activated. Since the locking mechanisms are also, accordingly, relatively small in dimension, activation of this mechanism requires precise and delicate maneuvering by the surgeon, which, in effect, manifests in excessive time spent in applying the strap assembly.
Accordingly, it would be desirable to provide a surgical device which assists the surgeon in applying a strap assembly about split tissue portions. The present invention is directed to such a device.